A valve timing controller is provide with a planetary gear mechanism and a link mechanism to vary a relative rotational phase between the first rotational element and a second rotational element, which respectively rotate with a crankshaft and a camshaft, so that valve timing of the engine is adjusted.
JP-2005-48706A shows a valve timing controller in which a guide-rotational element is rotated relative to a first rotational element by receiving a planetary movement of an external gear motion. A moving element which engages with a guide-groove of the guide-rotational element rotates an arm member of the link mechanism, whereby the relative rotational phase between the first rotational element and the second rotational element is changed. In this controller, there is a case in which the moving element is tilted relative to the guide-groove due to a clearance gap between the guide-groove and the moving element, which may be generated by manufacturing-tolerance. A friction coefficient between the moving element and the guide-groove increases, and a motion transmitting efficiency from the guide-rotational element to the arm member is deteriorated as shown by dashed lines in FIG. 7, when the valve timing is advanced or retarded. Hence, it may cause an operation-lock of the valve timing controller.
FIG. 16 shows a conventional valve timing controller. When a guide-rotational element 1000 rotates in a retard direction relative to a first rotating element 1002, a guide-groove 1006 biases a moving element 1004 diagonally downward left with respect to the radial line “r” as shown by an arrow Fb. The radial line “r” connects a rotational center “o” of the guide-rotational element 1000 and the moving element 1004. A movement of the moving element 1004 is restricted by the arm member 1008 connecting to the first rotating element 1002, so that the moving element 1004 moves diagonally downward right with respect to the radial line “r” as shown by an arrow Fa. As described above, when the direction in which the moving element 1004 is biased is different from the direction in which the moving element 1004 moves, the moving element 1004 hardly slide smoothly. Especially when the moving element 1004 is tilted, the motion transmitting efficiency is deteriorated.